There are many types of analog to digital converter technologies such as flash, sigma-delta, successive approximation routine converters, etc. These different styles of converter may be used in combination. In some converter topologies, an input signal is sampled onto a sampling capacitor (or an array of capacitors) prior to the analog to digital conversion taking place. During the sampling operation, charge is exchanged between the sampling capacitor and a circuit driving the analog to digital converter sampling capacitor. The driving circuit may have an impedance such that it takes time to charge and discharge the sampling capacitor to its correct voltage. This time will, to some extent, depend on the voltage across the sampling capacitor resulting from a preceding sample and convert cycle. Adequate performance should be obtained when the voltage across the sampling capacitor at the beginning of the acquire operation corresponds to the previously sampled voltage and has not been perturbed by the operation of the ADC.